51439988 has 6 divisors (see below), whose sum is σ = 90019986. Its totient is φ = 25719992.

The previous prime is 51439979. The next prime is 51439991. The reversal of 51439988 is 88993415.

It can be written as a sum of positive squares in only one way, i.e., 50865424 + 574564 = 7132^2 + 758^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6429995 + ... + 6430002.

It is an arithmetic number, because the mean of its divisors is an integer number (15003331).

Almost surely, 2^51439988 is an apocalyptic number.

It is an amenable number.

51439988 is a deficient number, since it is larger than the sum of its proper divisors (38579998).

51439988 is a wasteful number, since it uses less digits than its factorization.

51439988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12860001 (or 12859999 counting only the distinct ones).

The product of its digits is 311040, while the sum is 47.

The square root of 51439988 is about 7172.1675942493. The cubic root of 51439988 is about 371.9063721668.

The spelling of 51439988 in words is "fifty-one million, four hundred thirty-nine thousand, nine hundred eighty-eight".